UNIVERSITY OF ILLINOIS 


Agricultural Experiment Station. 


URBANA, JANUARY, 1902. 


BULLETIN No 68. 


IMPORTANT DETAILS OF SPRAYING. 


By ARNOLD V. STUBENRAUCH, B.S., M.S.A.. INSTRUCTOR IN HORTICUL- 
TURE, COLLEGE OF AGRICULTURE, AND ASSISTANT IN HORTICULTURE 
AGRICULTURAL EXPERIMENT STATION. 


INTRODUCTORY.—Within the last ten years there have been 
many bulletins and other publications on the subject of spraying. 
Nearly all of these treat the-subject from the standpoint of the 
kinds of mixtures to be used; some treat of the desirability of 
‘Spraying at all, but very few, if any, treat of the little technical 
details of the operation which constitute the fundamental principles 
and ‘which go so far to make successful results possible. The IIli- 
nois Station has already issued three publications on the subject 
(Circulars 8 and 37 and Bulletin 54); but they, too, may be in- 
cluded in the aboveclasses. While traveling over the fruit districts 
of Illinois during the past season the writer saw many well-meant 
but unsticcessful spraying efforts. The Illinois growers are en- 
thusiastic sprayers when once convinced of the practicability and 

157 


158 BULLETIN NO. 68. [ January, 


profit of the operation, and most of them are very well posted on 
the parts of the subject so thoroughly treated in the many publica- 


tions referred to. But upon the essential details a lack of knowl- 


edge is so manifest that it has been thought wise to explain thor- 
oughly the underlying principles, and thus give the growers of the 
state a chance to think and act for themselves in putting these 
fundamentals into successful practice. - 

Spraying is the most expensive of our orchard operations. It 
is at the same time the one most easily slighted, for it is the most 
exacting throughout the entire process. Good apparatus, pure 
materials, and, above all, patient and intelligent attention to every 
detail in the mixing and application are prime requisites for suc- 
cess. No part of the process can be slighted with impunity. It is 
not enough to go out whenever other work is not pressing and 
Squirt around in a hit.or miss fashion, expecting luck to do the rest. 
The time at which an insect pest or a fungous disease can be suc- 
cessfully combated or prevented is in most cases extremely short. 
Often a difference of a day or two is sufficient to change success 
into failure. Thus, in the case of the codling moth, as is well 
known, it is impossible to reach the worm after it has once got 
well into the fruit. So with the scab or the bitter rot: after the 


germinating tube of the fungus has once penetrated it, cannot be 


reached, and the mycelium will continue to grow and develop de- 
spite the presence, afterwards, of a fungicide. ‘The importance, 
then, of doing the work just at the proper time cannot be too 
strongly emphasized. When the proper time comes everything 
else must ‘‘take a back seat.” Get on the land somehow. If it is 
wet and muddy, devise some means of overcoming this: use a sled 
or put on extra wide tires—anything to get the work done at the 
proper time. Andfyou who have large areas to cover, be sure you 
have apparatus enough to get over the: whole place within the 
proper time. Steam and power sprayers are now coming into use 
both in New York and California, and there can be no doubt that 
after we know more about them we shall be able to adapt them to 
our conditions here. 

CLASSES oF MixtTurES.—Spray mixtures may be divided .into 


two general classes, depending upon the class of enemies they are 


intended to combat, viz.: 
1. Insecticides. 
2. Fungicides. 
Of the first class, there are two divisions or sub-classes, viz.: 
(a) Poisonous mixtures or solutions Zo be eaten by the in- 
sect along with the part of the plant or tree attacked. 





1902.] IMPORTANT DETAILS OF SPRAYING. IS9 


These mixtures are effective only against the chewing 
insects; e. g., codling moth, canker worm, tent-cater- 
pillar, leaf skeletonizer, and the like, and kill only after 
being eaten. In this respect they differ essentially from 

(b) Mixtures or solutions with more or less caustic or pen- 
etrating properties, which kill wholly by contact with 
the insect. This class of mixtures can be used effec- 
tively against both classes of insects, but is employed 
almost wholly against insects with sucking mouth- 

_parts, such as the scale-insects, the plant-lice, mealy 
bug's, and the like. These insects obtain their suste- 
nance by sucking the juices of the part of the tree which 
they attack, and cannot therefore be reached through 
their food supply. 

The second general class of mixtures, the fungicides, are also 
of two kinds, depending upon the character of the fungous disease 
which they are intended to check. “There are two kinds of fungi 
attacking living plants: ; 

(a) Those which grow on the surface of the parts attacked 
and which therefore have their mycelium exposed. The 
powdery mildews of the grape, the gooseberry, and the 
rose are the most common diseases of this class. 

(b) Those which grow wholly wzthzn the plant tissues, and 
which therefore have their vital parts, the mycelium, 
wholly protected from man’s attack. Most of the fun- 
gous diseases of plants belong to this class. The 
bitter and brown rots, the black rot, downy mildews, 
cankers, and hosts of other troublesome pests, all come 

| under this head. 

Naturally then, the remedies used against these classes of 
fungi differ materially in their action. The first mentioned are 
easily reached and £z//ed by the fungicide coming in contact with 
the exposed mycelium. ‘The remedies against the last mentioned 
class cannot reach the vital mycelium, and therefore can be preven- 
tive only in their action. The fungus must be checked before it 
penetrates. This cannot be too strongly emphasized; for upon 
this fact depends the successful use of the fungicides against this 
class of diseases. In order to bring out more clearly how thisiis, 
it will perhaps be well to get some idea of just what a fungus is 
and how it grows. 

Wuat Is A Funcus?—A fungus is a plant, differing essentially 
from the higher plants common to us in the absence of chlorophyl, 
or green coloring matter. It has its roots and stems, the mycelium, 


160 BULLETIN NO. 68. [ January, 


and its means-of reproduction and spread, the spores, analogous to 
the seeds of higher plants. Thespores are perhaps the most im- 
portant parts of the fungus, from the point of view of the fruit- 
grower, for it is by means of these that. the fungus is re produced 
and spread from leaf to leaf, from fruit to fruit, from tree to tree. 
Any agency which may disseminate the spores may be the means 
of spreading the disease. Winds, rain, birds. and insects are all 
known to act in this capacity. 

How a Funcus Grows.—Let us see, then, what happens when 
one of these spores falls, or is placed upon the surface of a leaf or 
fruit. As soon as the conditions of heat and moisture are favora- 
ble it will germinate, just as a seed does, and send out a tube, 
which, if it belong to the surface-growing class, will branch and 
continue growing on the outside, while if it be of the penetrating 
class, it will penetrate the skin and there continue its growth. 

How THE FUNGICIDE ACTs.—It is important toremember that the 
fungicide is non-effective against the spore itself; it is also, as has 
been pointed out, ineffective after the tube has penetrated. The 
germinating tube itself, therefore, is the only part of the fungus 
which is destroyed by the spray. Plate I. shows the appearance 
of the spores before and during germination, showing the tube 
against which the fungicide is effective. It will be seen, then, 
that the remedy is entirely preventive ; that the spore must germi- 
nate before the fungus can be destroyed and therefore the neces- 
sity of having the leaves or fruit emtzrely covered by the spray is 
strongly emphasized. If there are any breaks in the coating of 
the mixture, the exposed spot is liable to attack, and if attacked 
becomes a source of infection, the birthplace of a new crop of 
spores, ready to go out upon their mission of destruction. It will 
also be readily seen that good spraying is really cumulative in its 
effect, for naturally if we succeed in destroying all the way from 
80 to 100 per cent. of the germinating spores of a few seasons, the 
number will become so reduced that the attacks can be all the more 
easily and readily controlled. 


IMPORTANT DETAILS OF SPRAYING. 161 


1902. ] 


(a) Before germination. (b) During 
PLATE I. 
_ BITTER ROT SPORES AS SEEN UNDER THE MICROSCOPE. 


§ 





ermination. 


at he 
, 


162 BULLETIN NO. 68, s oe [ January, 


PHYSICAL PROPERTIES oF MixtTuRES.—Leaving aside their fun- 


gicidal or insecticidal properties and considering them solely 
from the point of view of their physical nature, we find that the 
classes of spraying compounds now in use may be grouped under 
three heads: 

1. Those involving the suspension of insoluble substances 
in water, e. g., Paris green, Bordeaux mixture, 

2. Simple solutions, e. g., ammoniacal copper carbonate, 
sulphid of potash, copper sulphate. 

3. Emulsions or mechanical mixtures of oily or waxy sub- 
stances with water. The most important of these is 
the kerosene emulsion, or, as at present used, the ker- 
osene water mixture without the use of an emulsifying 
agent. ' 

It is important to keep the differences between these classes of 
spray mixtures ever in view; for upon them depend not only the 
mode and manner of application, but also their action upon the 
insect or fungous pests which they are intended tocombat. It will 
be well, then, to consider each group in detail, and determine, as 
far as possible, the important points bearing EPO their behavior 
and handling. 

MIXTURES CONSISTING OF MATERIALS SUSPENDED IN WATER.— 
In the first class insoluble compounds are dealt with; and it will be 
noticed that they are to be suspended in water and applied while 
in suspension. It is important, then, that the mixture be thorough, 
in order that the material may be equally disseminated throughout 


the liquid. Suspension is brought about and kept up by means of. 


agitation. It is highly important, therefore, that the agitation of 
the mixture be most thorough, for, unless it is, two evils will re- 
sult—the first portion will be too weak to do effective work, and 
the last will be so strong that the trees will beinjured. The writer 
has seen the effects of this kind of spraying in this state. This 
may seem an old and well-known fact, but it is of far more import- 
ance than a great many growers suppose. 


SOMETHING ABOUT AGITATORS.—The agitators now in use are 
far from perfect or satisfactory, especially upon long, flat tanks; 
-and unless they are continually watched, unequal dissemination is 
likely to result. It is not to be forgotton that the liquid must be 
kept in motion ¢hroughout the tank. It is not alone necessary that 
a current be created near or around the opening into the pump. For 
this reason the whirling paddle is perhaps the best, especially. if 
constructed with tilted blades, something like a screw propeller. 
(See Fig. 1.) It is a common: practice nowadays to attach a paddle 


fay 7 


i¥ 


» Uae ¢ iy y > ¢ rs 4 A y os 
ext 2 . was 


1902.] _ (IMPORTANT DETAILS OF SPRAYING. sgh 163 


to ti pump handle, so that the agitation may be maintained with 
every stroke of the operator. At first sight this seems to be a good 
plan, but it is, really, a mistake. If the paddle is a satisfactory 
one, the labor to keep it going will be far too great when added to 
that of pumping, and, in consequence, the one will interfere with 
the other. Besides, a violent or quick motion is necessary for thor- 
ough agitation, while for pumping, a regular, steady stroke is the 
best. Therefore it is best not to attempt to couple the two motions. 
Paris green, when used 

alone, is, perhaps, the only 
material which requires 
continual agitation; and 
that, in the opinion of the 
writer, is a serious objec- 
tion to its use, now that 
lighter-grained poisons 
have been found which 
settle much more slowly 
and consequently do not 
need continuous agitation. 
If we omit Paris green 
from consideration, the 
liquids now in general use 
can be sufficiently stirred 
at short intervals — best 
while the rig is moving 
from one tree to another. 
A separate agitating de- 
vice is therefore prefera-_ 
Fic. 1. ble. The operator can 

| do more with the few vig- 

orous turns he is then able to give the agitator than is possible 
when the motion is dependent upon the pump handle. On large, 
flat tanks it is practically impossible to keep up a sufficient pres- 
sure and thorough agitation with the same stroke by hand. ‘Two 
or three paddles are necessary, depending, of course, upon the 
length of the tank. These can be connected to a lever on top, a 
few vigorous strokes of which, at intervals, will suffice to keep up 
‘a very thorough dissemination throughout the tank. The writer 
Saw a very effective and ingenious home-made device last spring 
used by a fruit-grower near Geneva, New York. This man had 
rigged up a pulley attachment to one of the wheels of his spray 
wagon. Over this pulley a belt was run, which communicated mo- 








Stes peg di 
164 BULLETIN NO. 68, . Zz [ ea 


tion to an arrangement on top of the tank for moving the agitating 
paddles. In this way the agitation was very easily and effectively 
maintained. Such an arrangement could very easily be put on at 
slight expense by any of the growers of this state. Of course, 
where steam or other power is employed both agitation and pump- 
ing are easily maintained by the engine or motive power. 

PRopER PLACING or Pumps on BARRELS.—Just a word about 
barrels. It is now almost the universal custom to place the pump 
on the end or head of the barrel. For the purpose of the class of 
spray mixtures now before us, it is very much better to have the 
pump on the side. When the barrel is laid and used on its side, 
as it must be in that case, most of the settling material will go to- 
wards the depression at the middle. It is therefore easier to keep 
it in motion, for the sloping bottom will aid in the work. As at 
present placéd, the flat bottom gives a larger settling area to con- 
trol, and will require more force to dislodge the sediment from 
around the edge of the bottom, while the comparatively straight 
sides retard rather than aid the necessary motion. If any one will 
place a small quantity of Paris green into a flat-bottomed tumbler 
containing water and then try to dislodge the grains sticking 
around the bottom, he will get some idea of the conditions which 
exist inside the upright flat-bottomed barrel. If you perform this 
little experiment, note at the same time how exceedingly difficult 
it is to dislodge the material by imitating the dipping motion of 
the paddles now in general use. Note also how very much more 
effective is a whirling motion. 

How To Spray ProperLy.—Having the mixtures properly pre- 
pared and thoroughly agitated cannot alone insure success. Unless 
the spray is properly applied, all preliminary effort is lost. To 
spray properly is more difficult than is usually supposed, especially 
where materials in suspension are used. It will not do to go out 
with a determination ‘‘to do a thorough job and give them an ever- 
lasting soaking” until everything is dripping. If this is done, there 
will be less material on the trees in the end than if less were applied 
in a proper manner. This to some may seem paradoxical. Never- 
theless, it isa fact, and an attempt will be made to show just how 
it takes place. In order to de this it will be necessary to consider 
the globules of water as they come from the nozzle, carrying with 
them suspended particles of Paris green or Bordeaux mixture, or 
both, as the case may be. The settling which takes place in the 
spray tank goes on within the globules of water after they become 
fixed to the fruit and leaves. Hence the larger the globule, the 
more settling will take place, and conesquently the more material 


1902.] IMPORTANT DETAILS OF SPRAYING. | 165 


will be deposited at one place. The only way this can be avoided 
is to have the globules very small and fine as they leave the nozzle, 
and to keep them intact as separate, fine globules after they become 
attached to the fruit or leaf. Hence, the importance of the injunc- 
tion: ‘‘Use only a fine nozzle; use force enough to keep the liquid 
ssuing as a fine mist; and spray only until the foliage and fruit are 
completely bedewed.” It requires considerable skill to do this pro- 
perly and cover the surface fully. If it cannot be done with one 
spraying, it would pay better to go over the trees twice, allowing 
the first application to dry before giving the second, than to try to 
accomplish it all at one time, and thusrun the risk of going further 
than the simple bedewing of the fruit or leaves. If the spray is 
_ continued too long, the fine globules will ‘‘run together” to form 
one or several large ones, which, instead of remaining fixed and 
drying just where they strike, will run down to the lowest place and 
drip. Of course, the suspended material settles to the lowest point 
of the globule, which is, in that case, spread over a considerable 
surface of the fruit. Some of the upper portions are thus left com- 
pletely bare. At the lower edge the material will drip off with the 
water, or often accumulate in sufficient quantity to cause injury. 
Plate II. shows reproduced photographs of glass plates sprayed with 
dilute milk of lime, having the same proportion of suspended ma- 
terial as Bordeaux mixture. (a) was sprayed just to the proper 
point and (b) beyond that point, or until the globules ran together 
and trickled down in streams. It will be noticed that (a) is quite 
uniformly covered, as is also the upper portion of (b), but note 
what has happened where the running together took place: The 
glass has been left perfectly bare in streaks, while at the ends of 
these little rivulets, the lime has accummulated, and where they 
dripped off the glass, the material in suspension went with them. 
Now, this is just exactly what takes place on the fruit and leaves of 
our trees. Plates III. and IV are examples of fruit and leaves pro- 
perly and improperly treated. The plates wereall made from pho- 
tographs, and show the imprints of the fine, separate globules, 
leaving the surfaces quite uniformly covered on the properly sprayed 
specimens, while the oversprayed shows how the running together 
has left a large portion exposed to attack. Where the bitter rot or 
_ the scab is very abundant, an apple ora leaf in the condition of 
those shown in Plates III. (b) and IV. is little better off than if it had 
not been touched at all. Unfortunately, plates which show the in- 
jury from the accumulation of Bordeaux or Paris green at the edges 
were unobtainable. Plate IV. showsa similar injury brought about 
by the accumulation of a soluble spray—the ammoniacal copper 


‘yurod aadoid ay1 01 ysnf pakesids (v 


oe) 
\O 
S) 
Z 
7; 
= 
(2 
4 
< 
5 
a 





1902.] _ IMPORTANT DETAILS OF SPRAYING. 167 


carbonate—by running down and evaporating at the edge; and it 
will serve very well to illustrate the injurious effect of such accu- 
mulation. (It may be stated here that these leaves were injured 
by a solution containing nearly ten times the usual quantity of 
copper carbonate, while the leaves of another tree properly sprayed 
with the same solution were not injured at all. The importance 
of precaution in this respect cannot, therefore, be too strongly em- 
phasized.) 

MIXTURES CONSISTING OF SIMPLE SoLurIONs. — 'The second class 
of spray mixtures, those which consist of diluted solutions, must be 
handled in different ways, depending upon whether the spray is 
to be used as a fungicide or an insecticide. If the former, then all 
the precautions mentioned before regarding the maintenance of the 
spray as a fine mist upon the surfaces, are necessary and important; 
otherwise the material will accumulate at the lowest point by evap- 
oration, and not only leave the upper portions unprotected, but may 
be seriously injurious, as in the case of the illustrations mentioned 
above and exhibited in Plate IV. If, on the other hand, the solution 
is used as an insecticide, intended to kill by contact, then a coarser 
nozzle and a direct stream is not only allowable but even desirable. 
In most cases the spray has done its work, if at all, just as soon as 
it has struck. It is not important then, that it remain on the trees; 
rather the reverse is often desirable. Of course injury from the 
accumulation by evaporation at the lower edges is liable to occur if 
too strong a solution is used, or if it is allowed to run down the 
tree trunks and saturate the ground around the root crowns, 


EMuLsions.—Mixtures of the third class are practically all used 
as insecticides against sucking insects,—scales, aphid, and the 
like, which, as mentioned above, can only be destroyed by contact 
with the mixture. Again, a large proportion of the mixtures of 
this class are intended for winter use, when the trees are dormant, 
and are, therefore, not subject to the same rulessas those used when 
the foliage is present. A somewhat coarser nozzle is essential, for 
in this case a direct stream, so that the mixture strikes with con- 
siderable force, increases the effectiveness of the spray. A great 
many of the insects of this class are protected either by a thick, 
waxy exudation or by a hairy or woolly covering, and, in order to 
penetrate these, it is necessary for the liquid to strike with consid- 
erable force. The writer has sprayed the plum aphis with kerosene- 
water mixture, using an ordinary fine Vermorel nozzle, without 
effect ; while the same mixture put on through a coarser nozzle, so 
that a direct stream was possible, did the work effectively. Inthis 
case, every part of the tree must be thoroughly wet, and it matters 





168 tee BULLETIN NO. 68, [ January, | 





(b) Oversprayed. 
PLATE: 
APPLES PROPERLY AND IMPROPERLY SPRAYED. 


IMPORTANT DETAILS OF SPRAYING. 169 














Ee 

| ee ‘ 

fe P . 

' 

AL J | 
{ 


eS 





PLATES LY. 


APPLE LEAVES SHOWING THE RESULTS OF THE ACCUMULATION OF THE SPRAY- 
ING-MATERIAL AT THE EDGES BY RUNNING-DOWN AND EVAPORATING. THE 
DARK EDGES AND SPOTS REPRESENT DEAD PATCHES ON THE LEAVES. 


170 BULLETIN NO, 68. ; [ January, 


little if there is some dripping. Care must be exercised, however, 
to avoid saturation of the ground around the root-crown by the 
liquid running down the tree trunks. : 


Paris GREEN, BorDEAUX MIxTURE, AND AMMONIACAL COPPER 
CARBONATE SOLUTION. 


So far nothing has been said regarding two of the principle 
factors in successful spraying, viz., the purity of materials and the 
proper methods of mixing. There are, perhaps, scores of mate- 
rials available for the destruction of insects and fungi, but for pres- 
ent purposes we need to treat of only the three in» general use in 
Illinois orchards—Paris green, Bordeaux mixture, and ammoniacal 
copper carbonate solution. Probably nine-tenths of the spraying 
done in this state at the present time is done with these three. 

Paris GREEN.——This substance, the aceto-arsenite of copper, 
was formerly manufactured solely for use as a pigment in painting. 
As such its prime requisite was a bright green color, together with 
some insolubility in water. Its composition was of little impor- 
tance. It has, however, now come into such extensive use as an 
insecticide—a use which makes its composition a prime requisite— 
that a demand has been created for a material specially prepared 
for this purpose. In the last few years this demand has been 
partly, at least, satisfied; and there are manufacturers who are now 
preparing Paris green solely for use as an insecticide. ‘The in- 
creased demand for the poison led to so-called improvements in its 
method of manufacture, resulting in a shortening of the time and 
a consequent increased product, but, of necessity, attended by 
less care in its preparation, until in late years the ordinary com- 
mercial Paris green, at best a variable compound, has become so 
exceedingly variable in its composition that its use has led to not 
only unsatisfactory, but even harmful results. ‘The experience in 
this state is no exception,.especially during the past season. Much 
dissatisfaction with the results of spraying operations has*been 
expressed on all sides. It is, therefore, highly important to point 
out some of the pre-requisites of a satisfactory article. 

In the first place Paris green should have its full complement 
of arsenic, for upon that depends its effectiveness as a poison. Thus, 
for example, if a fruit-grower use a green containing from one- 
fourth to one-half the quantity of poisonous principle presumed to 
exist therein, his spraying will fail to kill a large percentage of the 
worms unless the dose is correspondingly increased. Paris green 
should contain from 50% to 56% arsenious oxid, which, in the second 
place, should be Practically all in combination with copper. Free 


ero 2.) _* IMPORTANT DETAILS OF SPRAYING, ya ee 


arsenious oxid is soluble in water after a time, and when it is pre- 
sent in Paris green to any great extent, destroys one of the latter’s 
most valuable qualities as an insecticide, its insolubility in water. 
It is this latter quality which makes its use possible without injury 
to the foliage. Arsenious oxid in solution is at times extremely 
injurious. This seems especially true in drier localities or during 
dry spells having hot days followed by heavy dews or fogs at night. 
The dew dissolves the arsenic, which is then absorbed in sufficient 
quantities by the leaves to cause serious injury. This is as far as 


_ our knowledge goes at present. More investigation and experi- 


mental work are needed on this subject; for at times it has been 
possible to apply pure solutions of arsenious oxid without injury. 
But until we know definitely what conditions are favorable or un- 
favorable to the absorption of the arsenic, it is safe to use only the 
insoluble material. It is highly essential, then, that the grower 
know definitely just what grade of green he has to deal with. 
There are a few simple home tests which will show readily whether 
a sample is badly adulterated or not, but the determination of the 
exact composition can be made only with special appliances, or by 
some one with a knowledge of chemical analysis. The department 
of horticulture will examine and report upon samples of green sub- 
mitted by growers, so far as its means will permit. There is need 
for legislation in this matter, however; the department will second 
any efforts on the part of growers in this direction, and will be 
pleased to advise regarding the proper provisions of a Paris green 
law. . 

CoLor Txsts.—Perhaps the simplest test to determine whether 
a green has been extensively adulterated is the color test. Pure Paris 
green has’a bright green color, a shade or two lighter than emerald. 
Any samples which have a dull or a pale, washed-out appearance 
should at once be discarded without further question. By placing 
a small quantity in, say, a homeopathic vial, and tapping the latter 
gently on the bottom or side, adulterants can be made to separate 
from the green, and can then be seen as white streaks or patches - 
against the glass sides of the vial. The pure green remains bright 
green against the glass. In connection with the color test, Pro- 
fessor Woodworth of the California Station has devised the follow- 
ing simple test!, which can be made by any one and which will 
show immediately if the sample is worthy of any further consider- 
ation; Place upon aclean glass plate a small quantity of green, 
what one can easily pick up on the point of a pen knife ; tilt the 
plate at a slight angle and gently tap the edge, just enough to 


1 Bull. 126, Cal. Exp. Sta. “ Paris Green for the Codling Moth,” p. 12. 


172 / : BULLETIN NO. 68, [ January, 


cause the green to flow down leaving a streak across the plate. If 
the green is of good quality, the streak will be a bright, light em- 
erald green; if adulterated, a whitish or a sickly dull green. Any 
samples which exhibit the latter are either adulterated or of low 
grade and as such are not worthy of further consideration. 
-AmMoNIA TEst.—Another very simple way to show the pres- 
ence of adulterants is the ammonia test. Pure Paris greenis wholly 
soluble in ammonia, while some of its common adulterants are not. 
Therefore, if after dissolving a small quantity in ammonia, any res- 
idue remains undissolved, the sample has been adulterated and 
should be discarded. Unfortunately, this test does not show the 


presence of any free or uncombined arsenious oxid, which, although | 


it has not been considered strictly an adulterant (on the ground ofits 
poisoning qualities), is nevertheless objectionable on account of its 
injurious action onthe foliage. A large percentage of uncombined 
arsenious oxid may resu't from careless manipulation in manufac- 
ture. It is also often put in during manufacture to bring up a low 
grade green to the full strength of arsenic. In either case its pres- 
ence in the uncombined state is objectionable and should be known. 

Microscopic Trst.—One of the quickest and surest means of de- 
termining the presence of any adulterant or objectionable ingredient 
is the compound microscope. Placed under an objective of medium 


power, say one-quarter inch, Paris green is seen to consist wholly of — 


clean, green spheres, and ina pure sample this is all that can be seen. 
Plate V. is the reproduction of a photo-micrograph of a high-grade 
sample. A low-grade green will have something of the appear- 
ance shown in Plate VI. In addition to the clean, green balls a 
number of crystals are seen, which are almost wholly those of free 
arsenious oxid put in to make up the strength of a low-grade 
article. When the arsenic is added in the process of manufacture 
or results from careless manipulation, it is more difficult to detect 


it. In that case, it is usually found sticking to the green balls. 


themselves, giving them an irregular outline and causing them, on 


the whole, to aggregate into masses instead of remaining in sep-- 


arate, clean particles. The plate shows the appearance of these 
aggregates with their clinging crystals, but it is often very difficult 
to see them. | : 

The appearance of a wilfully adulterated sample, however, 
cannot be mistaken. In Plate VII. we have an exhibit of the marked 
characteristics of a sample which cannot be designated by any 
other term than ‘‘ bogus,” and so it has been labeled. This green 
was labeled ‘‘Strictly Pure Paris Green.” Note the long, needle- 
like crystals, which are, in all probability, those of gypsum, cal- 


1902.] IMPORTANT DETAILS OF SPRAYING. 173 





PLATE-V. 
' HIGH-GRADE PARIS GREEN AS SEEN UNDER THE MICROSCOPE 





PLATE VI. 
LOW-GRADE PARIS GREEN AS SEEN UNDER THE MICROSCOPE, ’ 


Sates Se PE 


174 BULLETIN NO. 68. [J/anuary, 


cium sulphate, and there can be no legitimate excuse whatever for 
their presence. These, together with the preponderance of the 





PLATE VII. 
BoGus PARIS GREEN AS SEEN UNDER THE MICROSCOPE. 


smaller crystals and the absence of the clean, green balls, make 
the name ‘‘ Paris Green” a fraudulent misnomer for this compound. 

ALLOWABLE Limit oF UNCOMBINED ARSENIOUS OxiIp.—Of 
course, it is practically impossible to manufacture an absolutely 
pure commercial Paris green without any uncombined arsenious 
oxid ; but it has been demonstrated that it zs possible to keep down 
the free arsenic below the danger point. In California this has 
been found to be about 4%, and that percentage has been placed 
as the allowable limit in their Paris green law passed last year. 
In many of the state Paris green laws (e. g., that of New York) 
no such limitation is made. It is well to note here that since the 
passage of the California law above referred to, it has been found 
that a number of the manufacturers are now producing two grades 
of green, one for the California trade, meeting the requirements 
of their law, and the other for sale in states where no restrictions - 
are placed upon the uncombined arsenious-oxid content. ‘This in 
itself is significant, and shows that it zs possible to manufacture 
a proper article. 3 . 


1902. ] IMPORTANT DETAILS OF SPRAYING. 175 


EFFECT OF THE ADDITION OF Lime.—It has long been known 
that the addition of lime lessens the injurious action of the free 
arsenious oxid by rendering it insoluble. This is true up to a cer- 
tain point. If the percentage of free arsenious oxid is very high 
the lime will do no good, and may even be harmful ; for it has been 
shown that lime acts upon white arsenic, when it is in suspension 
in water, in some way that greatly increases its injurious effect 
upon the foliage. 7 

-REQUIREMENTS OF A GOOD PaRIS GREEN.—We might, there- 
fore, sum up the points of a good Paris green as follows: 

1. It should be a wholly dry and impalpable powder. Gritti- 
ness and caking are evidences of adulteration. 

2. It should have a bright, light emerald green color, which 
should not whiten or become dull in the streak left in passing a 
Sample across a clean glass plate. 

3. It should be entirely soluble in ammonia. Any residue is 
an adulterant. 

4, Under the microscope it should be seen to contain only a 
trace of foreign matter, and should consist of clean, green spheres, 
wholly separate from one another. Aggregation into masses is 
evidence of careless manufacture. 


These are all the points which can be readily determined. In 
addition, to the above should be added the most important point, 
but one which can be determined only by a chemical analysis, viz: 

5. Paris green should contain not less than 50% of arsenious 
oxid, of which not more than 4% should be in the free state, or 
-uncombined with copper. 

OBJECTIONS TO THE USE OF PARIS GREEN.—Perhaps the most 
serious objection to the use of Paris green is the rapidity with 
which it settles in the spray tank. This renders the problem of 
agitation doubly important and difficult; for without the most 
careful attention and more satisfactory agitating devices than 
those now in use, it is practically impossible to secure a uniform 
distribution of the poison. There are differences in this respect in 
Paris green of different manufacture and even in different lots 
put up by the same manufacturer. A coarse, heavy-grained article 
' will naturally settle more quickly, other things being equal. 

It should be remarked here that when Paris green is used with 
Bordeaux mixture, the latter helps to keep the poison in suspen- 
sion. A few of the heavier. particles of the green go straight to 
the bottom, as they all do when used alone; but the majority 
remain mixed with the Bordeaux precipitate and settle slowly with 
it. If, therefore, Paris green is applied with properly prepared 


' 


176 BULLETIN NO. 68. [ January, 


Bordeaux mixture, much of the serious objection to its use, on the 
score of its rapid settling, will be overcome. ; 

SUBSTITUTES FOR Paris GREEN.—There have been so many 
objectionable features in the use of Paris green that different 
arsenical compounds have been suggested as substitutes. A few 
of these have been extensively tried and are very promising, 
especially where the mixtures have been home-made. Much has 
been said and written about the disadvantages, great labor and 
danger of preparing home-made compounds, and the advantage of 
Paris green in being ready to use just as it comes from the store. 
But it has now come to be generally recommended to add lime 
when preparing the green for use. This destroys the ready-to-use 
advantage of Paris green. Why not, then, go a step further and 
prepare a mixture of known composition and thus do away with all 
the uncertainties of commercially prepared articles? Several of 
the substitutes, notably the arsenate of lead and arsenite of lime, 
possess the additional advantage of being much smaller and lighter- 
grained, and consequently remain much longer in suspension. In 
addition, these can be used much stronger without injury. 

The home-made substitutes are growing rapidly in favor, and 
will, perhaps, largely supplant Paris green in the near future. 
The writer is at present investigating the properties of the differ- 
ent arsenical substitutes. While, apparently, very striking results 
have already been obtained, some points yet remain to be investi- 
gated, and the data will have to be reserved for a later publication. 

COMMERCIAL SUBSTITUTES FOR PARIS GREEN.—Of the com- 
mercially prepared substitutes, usually sold under the title of 
‘* arsenoids,” it need only be remarked that these are without excep- 
tion, perhaps, open to the objectionable uncertainties of all articles 
manufactured on a large scale; at least until manufacturers are 
willing to make their preparations conform to the rational require- 
ments of spraying purposes. 

BorDEAvUXx MIxTuRE.’—This fungicide is now the most gen- 
erally used and is perhaps the most important mixture employed in 
spraying operations. Discovered accidentally, about twenty years 
ago, its development has been remarkable, until at present it is 
noted as the best fungicide known. Fortunately, in this case there 
is little to fear from impure materials. Commercial copper sul- 
phate is so staple an article that so far not a single complaint has 
been brought against it on the score of impurity. Lime is more 
variable. In some localities it is exceedingly unsatisfactory, 


1. Four pounds copper sulphate, four pounds lime and fifty gallons water 
have now become the standard formula in Illinois. 


: 1902. ] IMPORTANT DETAILS OF SPRAYING. 177 


wholly on account of the poor class of rock from which it is manu- 
factured. Of course, where this is the case and poor lime must be 
used, it goes without saying that a larger quantity is necessary. 

Moreover, the quantity should never be gauged by measure alone. 
The ferrocyanide (yellow prussiate of potash) test is the safest 
way to determine the proper lime-content. For this purpose use a 
solution made up of about 1 oz. of ferrocyanide of potash to 5 or 6 
oz. of water. When the Bordeaux has sufficient lime the addition 
of a few drops of the solution wil! produce no discoloration ; but 
when insufficient, a dark brown discoloration results... Many simply 
‘pour a few drops of the solution into the mixture while in the tank 
or barrel. This is really not safe.. The slight discoloration, 
resulting from the presence of a small quantity of free copper sul- 
phate, cannot be seen in the spray tank. It is eminently desirable 
to have a// the copper in combination, and to be certain of this it 
is advisable to have a slight excess of lime, which does no harm. 
It is best, therefore, to dip out a small quantity in a saucer or 
other shallow white china dish for the test.. The slightest discolor- 
ation will then be visible against the white ground of the dish, 
Before performing this test it is necessary to have the liquid thor- 
oughly stirred. It is best to make two tests, giving a vigorous 
agitation between them. After such treatment the writer has 
often found the second test to result differently from the first. 
When they are both alike it is quite certain that the results are 
correct. As the ferrocyanide is a virulent poison it is essential to 
keep the solution distinctly labeled and out of reach of children or 
careless persons. When large quantities of stock solution of cop- 
per sulphate and lime milk are made up, one test with the ferro- 
cyanide will be sufficient for the whole quantity ; i. e., the one test 
will indicate the proper proportions for the stock solutions on hand. 
Another excellent method is to standardize the lime milk by mak- 
ing first a small quantity of test mixture. This can be done as 
follows: Make up the stock solution of copper sulphate as usual, 
one pound per gallon of water. Slake the lime, making of it a thin 
paste. Now take one pint of the copper sulphate stock solution, 
dilute to about a gallon, and add to that small measured quantities 
of the lime, testing after each addition, until the sulphate has all. 
' been ‘‘neutralized.’”’ From the quantity of lime thus used the neces- 
sary dilution can be calculated to make the lime milk any desired 
strength. The proportion of water necessary to make the proper 
dilution will be equal to the difference between the required 
strength and the quantity of lime milk used to neutralize the sul- 
phate, expressed in fractions of that strength. Thus, if one-half 


178 BULLETIN NO, 68. ‘, [ January, 


SSRN 6 





PLATE VIII. 


BORDEAUX MIXTURE PROPERLY AND IMPROPERLY PREPARED, AFTER SET- 
TLING TWENTY MINUTES. 


1902 ] 179 





Bee is : 


PLATE EX. 


BORDEAUX MIXTURE PROPERLY AND IMPROPERLY PREPARED, AFTER SET- 
TLING ONE Hour. 


180 BULLETIN NO. 68. [January 


pint is used in the neutralization, and if it is desired to have the 
lime of the same strength as the sulphate solution, it will require 
one-half pint of water for each one-half pint of lime milk; there- 
fore, the total quantity of the latter will simply have to be doubled, 
by adding an equal quantity of water. If only one-quarter pint 
was necessary to accomplish the neutralization, the total would 
have to be quadrupled, or three times the quantity of water 
added. In large-scale operations this standardizing of the lime 
milk will be found very advantageous, especially where the mixing 
is not all done by the same man. In this case, the standardizing 
can be done by the foreman, or head operator, and then the spray 
crews have simple, straight measuring to do. | 


PROPER METHOD OF PREPARING BORDEAUX MIxTURE, — Noth- 
ing but fresh or quick lime should be used. Air-slaked lime is 
very unsatisfactory and should never be used. Slake the lime 
carefully and slowly by adding the water gradually—just enough 
to keep.it moistened during the slaking process. In this way a 
clean, smooth paste will be formed, yielding a milk with very little 
grit, if the lime is of good quality. In keeping the lime paste 
through the season, it is essential to have it covered with water. 
If allowed to dry it will work up gritty, and vexatious clogging of 
the nozzle will follow. 

The proper mixing of the two slittions is of the utmost im- 
portance. Vever mix the concentrated solutions together, and always 
allow them to become thoroughly cooled before mixing. The lat- 
ter precaution applies, of course, when the sulphate is dissolved in 
warm water, and especially to newly slaked lime, which, on the 
whole, is better prepared at least twenty-four hours before using. 

To make Bordeaux mixture properly, dilute the copper sulphate 
solution and the lime milk before mixing them together; i. e., if 
50 gallons of mixture are being prepared, dilute each to about 
24% gallons. This will give a one-gallon leeway and thus allow 
the addition of more lime in case the test indicates a shortage. 


If these injunctions are not heeded, the resulting mixture will 
be very unsatisfactory, to say the least. If mixed concentrated 
and then diluted, or if mixed while warm, the precipitate will form 
in large flakes, which will not remain long in suspension and 
which cannot, therefore, be so effectively distributed. It is also 
probable that the compound of lime and copper thus formed may 
be different aud less effective. Plates VIII. and IX. are repro- 
duced photographs of cylinders of Bordeaux mixture properly and 
improperly made. ‘The cylinder on the left contained the mixture 
properly made by diluting the stock solutions before mixing. The 


1902. ] IMPORTANT DETAILS OF SPRAYING. 181 


mixture in the right-hand cylinder was made by mixing the con- 

centrated stock solutions and then diluting. ‘The pictures were 
taken after settling twenty minutes and one hour respectively, and 
show how widely different are the mixtures made by the two 
methods. In the first case, it will be seen that the properly made > 
mixture had hardly begun to settle, while the other had already gone 
down nearly six inches. After one hour, the properly made mix- 
. ture had settled only about an inch, the improperly made, about 
twelve inches. It will thus be seen how vastly important is the 
proper preparation of this valuable fungicide. A mixture with the 
“staying-up” qualities, shown in the left-hand cylinder, will not 
require constant agitation; stirring every ten minutes will be amply 
sufficient. A mixture like that in the right-hand cylinder could 
not be uniformly distributed without constant and most thorough 
agitation. ‘The saving of labor is alone sufficient to warrant the 
extra care, aside from the possibility of producing a more active 
fungicide. 

Mixine Ourtrits.—Where a large quantity of Bordeaux mix- 
ture has to be prepared, a good mixing outfit or elevated system of 
mixing tanks, will greatly facilitate the work. Such a system 
allows of easy and quick handling of the solutions and when prop- 
erly arranged will simplify the mixing operations, and consequently 
often avoid costly and annoying mistakes. There is opportunity 
here for the grower to display his ingenuity in devising an outfit 
which will best suit his purpose. Several such outfits are at present 
in use in Illinois. Perhaps the first to be constructed here is that 
devised in 1899 by R. A. Simpson of H. M. Simpson & Sons and 
used by him with great success during the past two seasons in their 
160-acre orchard at Parkersburg. It is the best of its kind now in 
use in this state. Mr. Simpson has kindly consented to give the 
fruit-growers of Illinois the benefit of his experience and has fur- 
nished the sketch from which the plan reproduced in Fig. 2 was: 
made, together with the following description of the system : 

‘*‘ (a) and (0) represent diluting tanks of 130 gallons capacity 
each. ~ | 

‘*(c) represents a mixing tank of 250 gallons capacity. 

_ **(d) is a very fine strainer (brass cloth wire, 20 meshes to the 
inch) attached to the bottom of a wooden box, which is supported 
by four legs long enough to reach to the bottom of the mixing tank. 

‘““(e)isa Sones force-pump capable of throwing a two-inch 
stream. 

‘* (f-g) is a piece of 2-inch hose to whicha pipe ( 2°) to (0) with 
a goose-neck is attached. 


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1902. ] IMPORTANT DETAILS OF SPRAYING. 183 


‘* (h) is a box for slaking lime. 

‘* (2) is a barrel of milk of lime made up from the lime paste pre- 
pared in 4, first run through a coarse sieve. 

‘“*(7) and (£) are barrels filled with copper sulphate stock solu- 
tion. | 

““( 7) isa piece of 2%-inch hose, through which the mixture 
from (c) runs to spray tank (7. ) 

‘*(m) is a Stake with a hook or other contrivance at its upper 
end to hold the end of the hose (/) above the level of the liquid in 
the mixing tank. 

‘*( pp) are spouts specially devised for throwing the liquids in 
wide, flat streams. ; 

‘‘The pipe (2°) to (6) can be moved by a man standing onthe 
ground, to either (2), (4), (2), (2), (7), (4), or any place within 
reach; thus allowing easy distribution of water to any point in the 
system. We get our water supply from ponds. 


“The mixing tank (c) must be so placed that the bottom will 
be a little higher than the top of the spray tank (7) when the latter 
is driven up to befilled. The bottoms of the tanks (a) and (4) must 
also be higher than the top of (c). It is also advantageous to have 
the bottoms of the tanks sloping forward, to allow of draining out 
the liquids. 

‘* When the system is put into operation, the hose (/ ) is hooked 
to the stake (m). If 4-4 strength of Bordeaux is being used and 
the spray tanks hold 200 gallons, lime milk containing 16 pounds 
of lime is taken from (z) and put into the diluting tank (a). Like- 
wise, 16 gallons of the stock solution, containing 16 pounds of 
copper sulphate, in (/) and (£) are put into diluting tank (4). Then 
100 gallons of water are pumped up into each of the diluting tanks. 
Then the diluted solutions are thoroughly stirred before turning on 
the faucets (ff). The latter are so placed that the thin, broad 
streams will come together and mix as they fall through the 
strainer (7) into the mixing tank (c). The mixture in (c) is then 
stirred, tested, and rectified, if necessary. As soon as this is done, 
the driver of the spray tank lowers the hose (/), thus allowing the 
mixture to flow into the tank at (7) where another strainer is placed. 

‘“If there should happen to be no empty spray tank in at the 
time the mixture is made up, the diluting tanks (a) and (0) are 
again charged as before, ready for another full tank of mixture. 
Then while the empty spray wagon is being filled, the faucets 
( pp) cat be turned on without waiting for the mixing tank to be- 
come empty. Thus two spray tanks can be filled without delay. 
We find that in this way one of our 200-gallon tanks can be filled 


184 BULLETIN NO, 68. [ /anuary, 


in three minutes, and as soon as one wagon pulls out there is a full 
tank of mixture ready for the second. 

‘‘Two men do all the mixing and test each tale with the 
ferrocyanide test for four 200-gallon outfits. Last year we aver- 
aged 5% tanks per day for each outfit, and in one instance 7% 
tankfuls were made and applied by one outfit in a day’s run. We 
find the mixture prepared in this way very uniform and satisfac- 
tory, and we are fully satisfied with the expenditure.” 

Mr. Simpson makes no mention of the cost of constructing 
such a system. It is probable, however, that it will involve con- 
siderable expense. If properly built and cared for, it will last a 
long time, and will no doubt prove a paying investment. 

The outline of this system is given as a suggestion to growers 
with large areas under cultivation. No doubt it may have to be 
improved or modified to suit the conditions at different places. 
Thus, for example, it may prove an advantage in some instances to 
construct a third and higher platform, upon which the lime paste, 
lime milk and copper sulphate stock solutions can be prepared. In 
this way the unbroken barrels of lime and sulphate can be hoisted 
up to the platform instead of being carried up piece-meal, as they 
are in the system described. Whether these added improvements 
would pay or not, must, of course, be decided by each grower for 
himself. 

Important Minor Deraris.—The lime milk should be care- 
fully strained, for despite the most careful slaking there will 
always be a quantity of gritty particles. There can be no doubt 
that straining is rather a tedious operation, but the writer has 
always found it to pay in the end, saving many vexatious and dis- 
couraging delays. It takes only a comparatively few gritty par- 
ticles to worry one for hours, and even days. If the strainer is 
made large enough, it will not be found to clog as do the small 
ones in general use. ‘The writer saw one operator who uses hun- 
dreds of gallons of Bordeaux, straining his lime milk through an 
ordinary milk strainer! That, of course, is time wasted. Where 
the lime milk is poured into an open barrel for dilution (asit should 
be for proper mixing) a 20-mesh brass wire strainer made to fit 
over the entire area of the barrel head will be found to work very 
satisfactorily. Such a strainer will, of course, have to be made to 
order, but it will pay in the end. 

Whenever the tanks or apparatus are to stand unused for a 
time they should be thoroughly cleaned. Merely filling the tanks 
with water will not do. All clinging particles of the mixture 
should be removed by running through a few gallons of cheap,vin- 


1902. | IMPORTANT DETAILS OF SPRAYING. 185 


egar or dilute acetic acid. Ifthe accumulated mixture is allowed 
to remain in the tanks or to dry in the spraying apparatus, scaly 
particles will form, and cause most annoying clogging of the 
nozzles the next time the outfit is used. 

These small details may seem unim- 
portant and tedious to many. They are, 
however, some of the little things, which, 
when neglected, may often prove the main 
causes of failure. 

AMMONIACAL CopPpER CARBONATE.—This 
solution consists of the commercial copper 
carbonate dissolved in diluted ammonia 
water. The proportions as recommended 
at present are: 


Copper carbonate .\. .c. 5. 45: 5 ounces. 
Ammonia (26° Beaume)...... 3 pints. 
WV ALGES © al oii Vasa ea nko de 50 gallons. 


This is a very valuable fungicide, es- 
pecially for late use when the discoloration 
of the Bordeaux mixture is objectionable. 
The solution is clear and of a light blue 
color and when dried upon the foliage or 
fruit leaves practically no stain. It is said 
to be not quite so effective a fungicide as the 
Bordeaux mixture—perhaps on account of 
the smaller amount of copper present in the 
strength of solution recommended. As com- 
pared with Bordeaux, the solution contains 
about one-tenth the quantity of copper, which 
is the active principle of the fungicide. 

Copper carbonate as commercially man- 
ufactured is pure enough for all practical 
purposes. The 26-degree ammonia water 
is more liable to variation. The nature of 
its composition is such that the solution 
(it is simply a solution of ammonia gas in 
- water ) is liable to become weakened by evap- 
oration. The commercial ammonia water 
when up to full strength (26° Beaumé) con- 
tains about 25% of ammonia, and it is upon 
that strength that the quantity required for 

FIG. 3. dissolving the copper carbonate is based. 
All of the copper salt must be dissolved ; therefore, if the ammonia 
water is weak, a larger quantity must be used, but no more than 





’ 


186 BULLETIN NO. 68, [ January, 


just enough to dissolve the carbonate. It is advisable for those 
who contemplate using this solution to any extent to provide them- 
selves with a ‘‘specific gravity spindle” (Fig. 3) for testing the 

strength of ammonia in the ammonia water they intend to use. 

Fill a tall cylinder (such as shown in Fig. 3) with ammonia water, 

and allow the spindle to floatin it. The depth to which the bulb 

will sink depends upon the density of the liquid. The stem of the 

instrument is graduated and the figure just at the surface indicates 

the specific gravity or relative density as compared with pure water. 

This specific gravity in turn indicates the percentage of ammonia 

gas in the solution, which can be found by reference to the appended 

table. ,With this test the grower is enabled to know exactly what 

strength of solution he has to deal with. Thus, dangerous guess 

work is avoided—an important factor in the use ef ammonia upon 

. living plants. 


* TABLE SHOWING PERCENTAGES OF AMMONIA IN SOLUTIONS OF THE-GAS IN 
WATER, AS INDICATED-BY THEIR SPECIFIC GRAVITIES. 


























Specific | Per cent of Specific Per cent of || Specific Per cent of 
gravity. ammonia. gravity. ammonia. || gravity. ammonia. 
. 900 9.51 .932 16.81 .904 24.39 
.958 10.03 .930 17.34 .9O2 24.94 
.956 10.54 .928 17.86 .QOO 25.50 
.954 11.07 .926 18.42 898 26.05 
.952 Ii, Sou wt .924 18.93 .896 26.60 
.950 12.10 .922 | 19.67 . 894 27.15 
.948 12.62 || .920 ) 20,01 892 27.70 
.946 Se $8 5) .918 20.56 .890 28.26 
.944 13.65 .g16 21.09 888 28.86 
.942 14.17 .gI4 . 21.63 . 886 29.46 
.940 14.69 .QI2 22.19 mi otoy rn as 30.14 
.938 15.21 .gIo 22.74 .882 30.83 
.936 15.74 .908 23.29 
.934 16.27 .906 23.83 











**Beaume 16° indicates .960 sp. gr. 
Beaume 20° indicates .936 sp. gr. 
Beaume 22° indicates .924 sp. gr. 
Beaume 24° indicates .913 sp. gr. 
Beaume 26° indicates .go1 sp. gr. 


METHOD OF PREPARING THE COPPER CARBONATE SOLUTION.— 
The ammonia should be diluted before using to dissolve the car- 
bonate. The writer has found the following method the most sat- 
isfactory for getting all of the copper salt into solution: First wet 
the carbonate thoroughly by making a thin paste of it with water. 


*Compiled from the Table of Lunge und Wernik, cited by Caldwell: “ Ele- 
ments of Chemical Analysis,” page 173. 


**Lodeman: “ The Spraying of Plants,” page 116, 


Tol 2 eae ns IMPORTANT DETAILS OF SPRAYING. 187 


Upon this paste pour one-third of the ammonia, say one pint to 
five ounces of carbonate, diluted seven or eight times. Stir vigor- 
ously several times and allow to stand until the undissolved salt 
has entirely settled. Pour off the clear liquid. Upon the remain- 
ing salt pour a second pint of ammonia diluted five or six times. 
Stir again and allow to settle as before. Pour off the clear liquid 
adding it to the first portion. On the remaining sediment pour a 
third pint of ammonia diluted two or three times (if weaker am- 
monia is used, no dilution will be necessary). This last pint 
should dissolve all the remaining sediment. If the ammonia has 
been found weak, add more ammonia until all the remaining cop- 
per salt enters into solution. Pour all of the solution together and 
dilute to the required spraying strength. If other than rain water 
is used iu diluting the ammonia, a cloudy, flocculent precipitate 
may be formed, which should not be mistaken for undissolved cop- 
per carbonate. ‘The latter is a light, bluish-green, flaky substance 
and can be easily distinguished from the darker, cloudy, larger 
floccules of the precipitate from the water. Wherever possible it 
is best to use rain water in diluting the ammonia for dissolving the 
salt. The floccules do no harm. The danger lies in mistaking 
them for undissolved carbonate and adding enough ammonia to . 
dissolve them. 


“aA 


188 | BULLETIN NO. 68, [January, 


PAGE 
Introductory 06 ee os ce ee eons bone 2 leo Wee ws Senn ala Signs emma 157 
Classes of Mixtures: .. Hi... 20 0e0 cvs oo vn «ala © piensa sle ane aen 158 
What is a Fungus 202)... 803s < eee ot seven «pele me 6 Ou inae ee anes 159 
How a Fungus Grows? 2.0. cc se coos ens oe olp oahta gs 01s nip ahs een 
How the Fungicide Acts.................- oe ae 8055) een ee gaa 160 
Physical Properties:of Mixtures. o..2- fc tees + Sine be eee ee mA eee 162 
Mixtures Consisting of Materials Suspended in Water....................-. 162 
Something about Agitators 2.0.0.8 o.oo ce oe bs gw wie wa gree ee 162 
Proper Placing of Pumps on Barrels). .....2.).. 022.05 se ete ee 164 
How.to Spray Properly. oo. 2c. foes cu tire as ap oe alg base eae oe sieita nn 164 
Mixtures Consisting of Simple Solutions:.... 2. .is... 2. 0... spate ee 167 - 
Emulsions 2... oc ccs oe vb bs 05 0 0.0 4 Sos ba pani Qisbalole>u in bs 6 pes tery astern ann 167 
Paris Green. ci... ve ceesw ses colsecwa agua tee gevde ciple ss «ts stati aan 170 
Color Tests... 0.6 oc sccm cic Siece wistennte*e niviae omnes ciety: iy» 0 iinet nan I7I 
Ammonia TeSt 2... occessinwe qa cp esc pwipteraeveig/e-ccp ia wiieiete cient nn 171 
Microscopic’ ‘Test 1 *..:) +2. 's. Ua asus optanece oti os eR capetk cite 172. 
Allowable Limit of Uncombined Arsenious Oxid.....................-- 174 
Effect of the Addition of Lime... 5.2450, occu uae ee Pay Pe aN 175 
Requirements of a good Paris ‘Green 2... . 2... [oct os oe eee 175 
Objections:to the Use of Paris Green ~...00 2.3 «. «aunt ee 175 
Substitutes -for Paris Green 2. co. e. 2c 0s 6. vs cone bs oe eee 176 
Commercial Substitutes for~Paris°'Green® .<.. i... ...0. «es eee 176 
Bordeaux Mixture. . 2. fc. 0200 Je bawe ends sans os ond 2 sie uate eee en 176 
Proper Method of Preparing Bordeaux Mixture..................- Toh 180 — 
Mixing Outfits 0.1. c.. svecn'es ewe wosabls bide te0 oible © cope enna 181 
Important Minor-Details 7.3 oo2.. o os aes a ee oe Eb cee 184 
Ammoniacal Copper Carbonate. 24 00.6. Soc. da ab 5 os me eee 185 
Method of Preparing the Copper Carbonate Solution................... 186 


